bin/51628: ypmatch doesn't match keys in legacy NIS servers

[Keith White]

>Number:         51628
>Category:       bin
>Synopsis:       ypmatch doesn't match keys in legacy NIS servers
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Apr 30 08:30:06 PDT 2003
>Closed-Date:
>Last-Modified:
>Originator:     Keith White
>Release:        FreeBSD 4.8-STABLE i386
>Organization:
SITE, University of Ottawa
>Environment:
System: FreeBSD admin16.site.uottawa.ca 4.8-STABLE FreeBSD 4.8-STABLE #32: Mon Apr 28 13:44:12 EDT 2003 kwhite at admin16.site.uottawa.ca:/usr/obj/usr/src/sys/XBAT i386

>Description:
ypmatch does not match keys in NIS databases that include the NULL
in the key field.

Databases that started out on SunOS 4.X, say, include NULL in both
the key and data fields.  This makes it impossible to use ypmatch
to check for the existence of keys since the terminating NULL
is removed prior to calling yp_match().

Try this against a SunOS 4.x NIS server: 
  $ ypmatch @ aliases
  ypmatch: can't match key @ in map mail.aliases. reason: No such key in map

Try it at the same time on a Solaris host:
  $ ypmatch @ aliases
  @

(FWIW the '@' key is used to signify that the NIS aliases database is
up-to-date.  When it doesn't exist the aliases database is in the
process of being updated.)

>How-To-Repeat:
>Fix:

The following patch will do another yp_match() call including the
terminating NULL in the key if the first call failed.

--- ypmatch.c.orig	Wed Apr 30 10:02:54 2003
+++ ypmatch.c	Wed Apr 30 10:04:55 2003
@@ -29,7 +29,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-  "$FreeBSD: src/usr.bin/ypmatch/ypmatch.c,v 1.7.2.2 2002/02/15 00:46:56 des Exp $";
+  "$FreeBSD: src/usr.bin/ypmatch/ypmatch.c,v 1.7.2.X 2002/02/15 00:46:56 des Exp $";
 #endif /* not lint */
 
 #include <sys/param.h>
@@ -117,6 +117,18 @@
 
 		r = yp_match(domainname, inmap, inkey,
 			strlen(inkey), &outbuf, &outbuflen);
+/*
+	If we failed, try again including the terminating NULL in the key.
+	Some NIS servers include the NULL, notably SunOS 4.X.
+*/
+		if (r != 0 && r != YPERR_YPBIND) {
+			r = yp_match(domainname, inmap, inkey,
+				strlen(inkey)+1, &outbuf, &outbuflen);
+			if (r == 0 && outbuf[outbuflen-1] == '\0')  {
+/* since we added a NULL, let's remove it from the result */
+				--outbuflen;
+			}
+		}
 		switch (r) {
 		case 0:
 			if (key)
>Release-Note:
>Audit-Trail:
>Unformatted: